Background

The periprocedural risk of cardioversion in atrial fibrillation (AF) is substantially increased if patients are not adequately anticoagulated (5-7% vs. 1% of patients on vitamin K antagonists (VKA)). VKA are currently standard therapy before and after cardioversion, but at least 3 weeks of VKA use is needed to reach an adequate level of anticoagulation. Because of their shorter half-life, new oral anticoagulants (NOAC) could be an attractive alternative. To date, only post hoc information is available, however, with regard to the use of NOAC in this situation.
The X-VERT study compared the use of oral rivaroxaban once daily with adjusted dose VKA in patients with non-valvular AF who are undergoing elective cardioversion. The X-VERT study is a prospective, randomised, open-label, parallel-group, multicentre, active comparator study into the efficacy and safety of rivaroxaban in the reduction of cardiovascular events (primary endpoint: stroke, TIA, non-CNS systemic emboli, myocardial infarction, and cardiovascular mortality). Both early (1-5 days, n=872) and late (>21 days, n=632) cardioversion were investigated (according to investigators judgement based on guidelines). Follow-up was a maximum of 100 days.

Main results

Only 10 patients experienced a CV event (5 of 978 patients on rivaroxaban and 5 of 492 patients on VKA). A non-significantly lower number of patients experienced the primary endpoint as compared with VKA (0.51% vs 1.02%, RR: 0.50, 95%CI: 0.15-1.73).

In the group who underwent early cardioversion, there was no difference in the delay between the treatment groups, while patients on rivaroxaban who underwent late cardioversion showed a shorter delay (median: 22 days vs. 30 days, P<0.001).

In the delayed group, 1 patient on rivaroxaban showed insufficient anticoagulation (77% was cardioverted according to plan), as compared to 95 patients on VKA (36.3% was treated according to plan).

Conclusion

This first prospective, randomised study into use of a NOAC in patients with AF who have to undergo elective cardioversion, shows a low and similar incidence of the primary endpoint for rivaroxaban and VKA-treated patients. Also the occurrence of bleeding was comparable in both groups. Time to treatment was significantly shorter with delayed cardioversion in patients treated with rivaroxaban. Oral rivaroxaban 20 mg once daily therefore seems to be a safe alternative for VKA, which allows prompt elective cardioversion in patients with AF.
In the discussion during the press conference, is was discussed that the current statistical power in this study was the only feasible option, considering the low frequency of events. These results confirm and expand the already available evidence, and offer cardiologists the necessary information on what to do with patients on NOACs who need cardioversion.